Review of December Meeting
Wednesday 12th December 2007
Science with a Smile – a talk given by:
Dr.Percy Seymour, retired Principal Lecturer in Astronomy at the University of Plymouth
Chairman of Sherborne Science Cafe
Dr. Seymour thanked everyone for a successful first year for Sherborne Science Cafe, before starting his lively, informative talk on subatomic physics, astronomy and Einstein, which was peppered with his endless supply of hilarious jokes keeping the audience entertained all evening, while explaining some difficult scientific concepts.
Mnemonics are topical at the moment and Dr. Seymour quoted several which help scientists to remember facts as diverse as the age order of rocks in geological time, to rhymes to learn the numbering of stars in the spectral sequence. He described how stars emit light of different colours, explaining how this numbering problem was first addressed. The German teacher, Doppler, thought star colour was dependent upon speed, but this is now known to be incorrect. A hot body’s colour depends upon its temperature. Because of the atmosphere, a bar code effect appears on the spectrum when light is passed through a prism. To begin with astronomers used spectral lines of hydrogen to classify stars; the brightest stars tending to be bluish, the less bright more reddish, with our yellow sun being fairly central in this spectral classification. All concepts were clearly illustrated with colourful diagrams.
Dr. Seymour then described how radar speed traps work. The wavelengths of radio waves appear to be pulled out with increasing speed, so when aimed at a moving vehicle, a speeding car would cause the waves to take longer to return to the radar device, thus triggering a camera if the speed were excessive.
He developed this theme to explain how in the subatomic world, when light or radiation is beamed at an object such as an electron, it is only possible to measure either its position or its velocity, as taking the measurement of one variable, automatically alters the knowledge or measurement of the other. This is Heisenberg’s Uncertainty Principle.
All atoms have lifetimes which as they decay, give off radiation. The study of atomic decay gave rise to the discovery of a new particle, the neutrino.
Next for explanation, was The Special Theory of Relativity, where Einstein predicted that if an object were travelling at 75% of the speed of light, any observers would see a foreshortening of that object. He also predicted that clocks would slow, the closer an object travelled to the speed of light. This dilation meant that time would appear stretched out for travellers. Einstein also predicted that as objects approached the speed of light, they would also become heavier. These theories have since been proved.
Finally, Dr. Seymour discussed Einstein’s General Theory of Relativity with the idea of space-time being distorted because of massive bodies in space. The final limerick summed up the complexity of Einstein’s theories, rounding off an interesting, stimulating evening.
There once was a family called Stein,
There was Gert, there was Ep, there was Ein.
Gert’s poetry was bad,
Ep’s sculpture was worse,
And no one could understand Ein!
Review of November Meeting
Arthur Davis, President of Crewkerne Astronomical Society
Arthur Davis first acquired an interest in astronomy when serving in the Navy, experience which was to prove invaluable when designing and building equipment for astronomical observations over more than 50 years. One particular fascination has been the sun. Arthur introduced the talk with a brief description of the size, structure and age of our galaxy. Our sun was formed about 5 billion years ago, and sits about two-thirds of the way out from the centre of the galaxy. The size and structure of the sun was described, and some of the surface features illustrated with images taken by X-ray imaging, as well as optical imaging of the emission line spectrum from hydrogen.
Observations of the sun are difficult for the amateur astronomer, and conventional optical techniques need to be adapted. The sun is very hot, and consequently very bright, and should never be observed directly with the eye, particularly through a telescope. The telescope needs to be fitted with filters, or the image projected onto a suitable screen. With such modifications it is possible to observe sunspots, and these were illustrated and explained.
The structure of the solar system is such that at times the planets and their moons can be in alignment with the sun, and eclipses occur. The sun, the earth and our moon form a unique combination in the solar system in that the apparent diameters of the sun and moon are very similar. Thus it is possible for the shadow of the moon to completely cover the sun. In such a case there is a total eclipse. Since the moon and earth move in slightly elliptical orbits, their distances from the sun vary slightly. On some occasions the moon’s shadow may be slightly smaller than the sun, and an annular eclipse occurs, where a ring of the sun’s disk is still visible. If the sun and moon are not in complete alignment the eclipse is partial. Eclipses only occur at the time of a new moon, but the times when the alignment is exact are rare. For example, the last total eclipse seen from Britain was in 1999, and the next will be in 2090.
Eclipses allow other features of the sun to be observed, including the sun’s corona, flares and prominences, and these were all illustrated with examples taken by Arthur using his own equipment. The particular types of telescopes most suitable for photographing eclipses were described, as well as the modifications necessary for optimum imaging.
Arthur’s first eclipse was in 1973, when observations were made from on-board a ship, off the coast of West Africa. The eclipse lasted nearly 2 ½ hours, including 5 minutes of totality (the maximum possible is 7 minutes). One particular problem when observing from a ship is to allow for the movement of the deck. Equipment was designed with a gimbal mounting and counterweights to stabilise the telescope; Arthur’s naval experience was useful here.
Among the most memorable total eclipses were those of 1983 (in Indonesia), 1991 (Hawaii), 1994 (in South America) and 1995 (India). The 2005 eclipse (in Spain) was annular. All were well illustrated and described.
A similar phenomenon to an eclipse is a transit: the passage of one of the inner planets between the Earth and the Sun. Being much further away than the moon, the shadow of the planet is much smaller. Images of the transit of both Mercury (1970&2003) and Venus (2004) were shown, including a particularly interesting sequence showing the passage of the shadow across a sunspot. Observations of transits were among the first methods used to estimate the size of the solar system, a technique first suggested by Halley in 1716.
Arthur has seen 10 total and 2 annular eclipses over the last 30 years (even more than Sir Patrick Moore!), which by coincidence always seem to occur in interesting and exotic sites. As well as fascinating images of the variety of phenomena to be seen at the time of an eclipse, we were entertained with pictures of the many places Arthur has visited.
The talk concluded with a lively discussion.
SOFTWARE EXPOSED -A PRESENTATION BY ALLAN LAWTON
Many people have computers in their homes. The visible features of our computer systems – keyboard, monitor, tower, printer, scanner and other peripherals – are the most obvious parts of the set-up, but to turn this hardware into a useful and operational system, we need software. Allan Lawton, a senior Software Manager from Thales in Templecombe, let us into the secrets of software.
Allan started his talk with a brief history of computers and software, starting with the use, by the Chinese, of algorithms on their Abacuses, and ending with modern programmable electronic computers. He briefly mentioned Charles Babbage, who invented a mechanical device, called a difference engine, and as a result is considered to be the Father of the Computer.
He then went on to discuss the stimulus given to computers by the need to decode enemy messages during the World War II. This gave rise to the work of Alan Turing (who was educated at Sherborne College) in England, and John von Neumann in the states. These two men did a great deal to set the tone of modern computers.
This led on to a discussion of the development of different computer languages. He also briefly mentioned the accidents and, sometimes, the deaths, that arose from bad programming of computers used to operate planes, rockets and medical equipment.
The V Life Cycle of purpose designed software was then discussed. This started with a clear statement of the requirements, then the detailed design, followed by coding, code tests, systems tests and finally acceptance tests. This was followed by an outline of software design methods, including: flowcharts, the use of case diagrams, sequence diagrams, class diagrams, state chart diagrams and object-orientated programming.
The talk ended with a demonstration of the JAVA language. There was lively discussion at the end and the evening turned out to be a good introduction to the complexities of the world of software design.
Forensic Art by Mike Levenson
On Wednesday, 12th September, Mike Levenson, forensic police artist,
presented an extremely topical, informative talk about Forensic Art to
Sherborne Science Cafe, at Sherborne House, Newland.
Mike trained as an artist before going to work in Arlington, Virginia with the FBI. He later attended Manchester University where he followed a course on 3D skull reconstruction.
He began with a whistle stop tour outlining how from the earliest cave paintings, man has used pictures to communicate. Hunters drew exaggerated charcoal images of large animals towering over tiny people to pass on their exploits to children.
Ancient Egyptians used art extensively, depicting humans with only one eye; two eyes being reserved for higher beings. An Egyptian scroll from 455BC in the British Museum, showing an address on a slave’s belt, is the earliest known example of forensic art being used to catch a criminal. The slave stole some jewellery and promptly disappeared. His master commissioned an artist to draw details of the belt, which was not allowed to be removed. The thief was identified, caught and dealt with appropriately.
All small boys recognise the importance of “Wanted Dead or Alive” Posters in the American Wild West. The artist might draw regular offenders’ portraits while they were in jail, or from witnesses’ descriptions. Unfortunately the usefulness of these posters declined as artists could be bribed to make the portraits unrealistic, or appearances could change over time.
In 1829 the first police force, the Met., was established in London, replacing the old Bow Street Runners.
By 1888 there were between five and eight newspapers reporting the events of the capital. Then Jack the Ripper killed his five victims, two on the same day. He was only active for a couple of months but such is the power of the media, that by the end of his reign of terror the newspapers had increased to over a hundred.
Often comic strip format would have been used because of the literacy problems of the general population, but backed up by a written report for the better educated. Witness statements were by now being used and information passed on to artists for interpretation.
By 1910, the Italian Alphonse Battillian suggested photographing criminals from the front and the side and also noting any identifying features. This method is still in use today.
The Canadian Mounted Police used Identikit pictures to build up an image which could be reproduced exactly by careful use of coordinates. More realistic Photofits replaced these. With the advent of computers, sophisticated Electronic Efits, capable of over a billion changes without repeat, came into general use.
However, photographic identification remains difficult, as change of hairstyle or the addition of glasses can radically alter appearance.
One area where photographic reconstruction can be invaluable is in the age progression of missing children. If a child of two or three years of age goes missing, it is possible to create a near likeness several years into the future. Scientists know exactly how the skull develops over time. By taking a recent photograph of the missing toddler and combining it with a photograph of a close relative, a very near match can be obtained.
Fingerprints, ear or toe prints, even casts from teeth bites, can all be used to help positive identification.
Yet another exciting development in forensic science, is the development of 3D skull reconstruction. The British are at the forefront of cutting edge technology, where a plaster cast of a skull forms the basis of a model where layers of clay are built up to create sinews and muscles, before the flesh is added to produce a lifelike sculpture. A truly fascinating talk.
Martin Crozier - Life is a game
Martin explained that Games Theory is a branch of mathematics and economics where multiple players make decisions in attempts to maximise their returns. Each player develops a strategy which will hopefully always give the best solution to the problem, although interestingly, this will not always solve the game. Often, as in noughts and crosses, players only win outright if an error is made by the other player(s). Game Theory assumes the ambition to win, maximising your options, or reaching a mutually acceptable compromise. In multiple player scenarios, this may involve liaisons with other people, uniting against other opponents.
Computer models demonstrated how, when choosing from a multitude of strategies, such as Tit for Tat, Cooperation, Dominance, Mistrust, Nasty, etc. That Tit for Tat usually won the game. Maybe Dad was right after all when he suggested that Little Johnny would be better off hitting Little Freddie back, rather than adopting Mum’s more conciliatory approach when there was trouble in the playground!
Game Theory is increasingly applied in the real world. It is used in social sciences and diverse academic fields. From the 1970s it has been applied to animal behaviour, including evolutionary theory. Computer scientists use it for studying artificial intelligence and cybernetics.
Game Theory was used in World War 2 for the allocation of defences for attacking enemy bombers. No doubt even more complex strategies are applied today. Experiments are currently taking place where colonies of bacteria are being studied to see if, and how, they cooperate to take over other colonies. We are not the only creatures seeking dominance!
In economics Game Theory is widely used to model stock market movements.
Major companies, like Marks and Spencer or British Home Stores, use it to calculate sales plans or marketing strategies to beat rivals on the High Street.
It can even be used by footballers analysing where to aim the penalty kick.
Many fascinating facts were revealed during the talk. There is no Nobel Prize for Mathematics, although John Nash, the mathematician and subject of the film “A Beautiful Mind”, won it for economics in 1994. Many noted scientists are also mathemeticians.
Westland Helicopter World Speed Record
Report of meeting on 13th June 2007
On 13 June 2007 Sherborne Science Café was given a talk on the breaking of the helicopter world speed record. Westland’s former Chief Engineer Geoff Byham and ex-Chief Test Pilot Trevor Egginton shared an entertaining and informative talk which included video footage of the record-breaking flight.
Geoff Byham started by outlining the background against which the decision was taken to make an attempt on the outright helicopter world speed record. Westland had held the Lynx Class record previously, but it had been taken by a Sikorsky S76. A Russian military helicopter, the Mil Hind held the outright record which stood at 368 k/h. By 1985 Westland was facing financial problems following difficulties with an order for W30 helicopters to India, and political complications (including ministerial resignations) had led to damaging publicity for the company. In contrast the technical strength of the company was very good, and it was involved in a number of new developments, including the successful flight testing of an innovative rotor design. With a view to making a major impact in time for the Farnborough Air Show of 1986, the Westland Board agreed to release resources for an attempt to be made on the record.
Working within a very modest budget and even more challenging timescales, a project group was assembled, including engineering and flight hangar staff. Among the considerations that convinced the group that the record was possible were the success of the new rotor technology, the possibility of boosting the engine power, the ability of the gearbox to cope with the increased power, the vibration characteristics of the airframe, and calculations on the reduction of drag and overall weight. In addition it was decided to use pre-injection of a water-methanol mixture into the engine air intake in flight in order to boost the mass flow of gas to the engine as a way of further increasing power. Success depended heavily on the active cooperation of the engine manufacturers, Rolls Royce, but could not have been achieved without the contribution made in-kind by the MOD and the generous involvement of over thirty British-based companies who supplied components and systems to the Lynx. In fact the project received universal approval, and many generous offers were made, both financial and “in-kind”.
It was decided to use the company demonstrator Lynx helicopter, G-LYNX, but this had not flown for 2 years and was a major challenge to the hangar team to be made ready. All modifications had to be approved by measurement or detailed calculation and design considerations. By the nature of the project there were changes that had to take place very late in the day. These included repositioning the tailplane and optimising the exhaust profile to suit the anticipated ambient temperature at the time of the record attempt.
Trevor Egginton was the test pilot on the record attempt, and described the requirements set by the Royal Aeronautical Club for the observation and timing of the runs. Four passes over a measure 15km course were measured, and the average speed for the best two successive runs was calculated. The highest speed achieved was 400.87 k/h, beating the previous record by 33k/h. The modified Lynx was the first helicopter to take the record beyond 200 knots, and only narrowly missed the 250 mph barrier.
Both speakers agreed that the project was immensely satisfying: the teams worked well together, all targets were met, and design predictions correlated very closely with the flight test measurements.
As a finale a video was shown of the actual record attempt over the Somerset Levels.
THE MIGHTY ATOM
SHERBORNE SCIENCE CAFÉ
The audience at the café, which meets at Sherborne House, were treated to an informative, entertaining, and, at times, an amusing talk on the basic ideas and practical applications of nuclear medicine. The lecturer was Bob Barber, formerly Divisional Head of Nuclear Medicine, Addenbrooke’s Hospital, Cambridge.
In the first half, Bob, gave a very concise introduction to the relevant discoveries. These included Wilhelm Roentgens' x-rays 1895, Henri Becquerel’s radioactivity in 1896, Joseph Thomson’s discovery of the electron in 1897, Rutherford’s work on identifying the different types of radioactivity and the Bohr-Rutherford model of the atom.
Bob said that the work of the English physicist Paul Dirac was the pinnacle of work on the quantum theory of the atom, and Einstein’s theory of relativity, because it combined relativity and quantum theory. However, the most astonishing prediction to come out of Dirac’s work was the possibility of the existence of a particle with the same mass as the electron, but with a positive electric charge, rather than a negative one! This particle is now called a positron.
The second half concentrated on the application of nuclear physics to various problems in medicine. Much of this discussed various ways of imaging parts of the human body. Several elements come in different forms, called isotopes, which have similar chemical properties to their parent elements, but their atoms differ from the parent in mass and they are radioactive. Some of these radioactive isotopes (called radionuclides), especially if they lose their radioactivity within several minutes, or a few hours, can be injected into the human body, where certain of the isotopes can be taken up by different parts of the body, and the radiation they emit can be use for imaging. The radionuclides is usually attached to a suitable compound chosen for its ability to go to the organ of interest.
Dirac’s positron has come into its own in one method of imaging. Fluorine 18, a radioactive isotope, which loses half its radioactivity in just less than two hours, can be injected into the body, and when it decays it gives off a positron. This particle will very quickly meet up with an electron close by, and when the two annihilate each other, two gamma ray particles will be emitted in opposite directions. By using counters around the body to pick up these two particles simultaneously, it is possible to pin-point where they came from, and this can be used to build up an image of the part of the body in which they were located. This technique is called Positron Emission Tomography or PET.
The meeting ended with several questions about the scientific principles involved, and some about the cost of the equipment used, and the distribution of hospitals where such equipment was located.
Sustaining Our Jurassic Coast
On Wednesday 14th March 2007, Tony Flux, of Dorset Coastal Forum entertained Sherborne Science Cafe with a fascinating whistle stop virtual journey along the length of Dorset’s Jurassic Coastline from Lyme Regis to Studland Bay. He explored a multitude of wide ranging management issues from pollution crises, to the possibility of huge cruise liners berthing at Portland, to coastal erosion, or generating tidal energy, through to the growth of tourism and water sports, to the management of the influx of competitors, officials and visitors expected for the 2012 Olympics.
After the Napoli disaster plans to deal with possible future oil spillages had to be extended to deal with beached containers! Most of the audience was unaware that Russian oil designated for shipment to the United States is now transferred to supertankers off Lyme Bay. Russia uses smaller tankers on account of the shallow draft of the Baltic Sea. Finland objected to oil transference off its shores because of the dangers of spillage and pollution, so now it happens here!
Another interesting fact that emerged is that as Portland harbour is deep enough to accommodate huge ships, there is a possibility of cruise liners carrying 4 -5000 passengers docking there in the future. This begs the question of what to do with this influx of visitors. Do we have the infrastructure to ferry so many visitors to Stonehenge, Stourhead or wherever?
A novel solution has been offered for accommodation for competitors and officials expected for the 2012 Olympics. The International Olympic Committee decrees that a minimum standard of 4 Star accommodation is required, so Fred. Olsen has been contracted to moor some of his cruise liners here as luxury floating hotels!
Since the Dorset Coast was granted World Heritage Site Status by UNESCO in 2001, the Dorset Coast Forum have become world leaders in the management, protection and sensitive development of such sites, attracting experts from as far away as Australia, New Zealand, Japan or the US who come to learn from our experience.
Management of our Jurassic Coast is ongoing and ever developing. If global warming proceeds at predicted rates, there could be a 23cm, (9”) sea level rise in Poole Harbour by 2030. Should the sea be allowed to encroach or should measures be taken to hold it back? Many such questions were posed throughout this interesting evening providing much food for thought.
The Development of the Bio-ethanol Industry in the UK
On the evening of St. Valentine’s day, a large audience forsook romance to hear John Waltham of Green Spirit Fuels speaking to Sherborne Science Café at Sherborne House and it was well worth the ‘sacrifice’! John spoke with obvious passion and expertise about the locally emerging Bioethanol Industry at Henstridge and stimulated considerable discussion from professionals in the ‘field of grain’ and ‘green’ members of the public alike.
Green Spirit Fuels was launched by Wessex Grain in 2005 in response to the increasing demand for Biofuels but also to utilise excess grain. Planning permission was granted for the site in January and it is hoped that building will start in 2-3 months with production commencing in 2008, when it will be the first industrial Bioethanol producer in the UK.
Dried and milled grain is by treated by a series of steps, which include the addition of amylases, to burst the starch grains and convert the starch to sugar and then a lengthy fermentation process occurs with the addition of zymases over a period of 10 to 14 days. The alcoholic ferment is distilled to give a 40% alcohol\water mixture and further distillation increases this to a 91% mixture. Molecular sieves remove more water to give finally 99.7% pure ethanol, (which is subsequently ‘doctored’ to avoid duty and preserve livers). Meanwhile, the spent grain\water is decanted and dried giving a ‘wet cake’ and also a syrup which is pelleted for animal feed. The ‘wet cake’ is burned to release energy or anaerobically digested to yield methane which will drive turbines, generating energy for the National Grid and other by-products. CO2 produced during fermentation is sold for the manufacture of fertilisers, for which there is a ready market.
I find the total concept quite beautiful; it is carbon neutral in the overall cycle, CO2 generated being removed by the subsequent year’s grain production; it has an energy efficiency of 2.5 utilising energy produced on site for any heating processes and even contributing to national supplies; no waste is produced as every fraction is used. There are many good reasons for the use of British grain: it contains the highest starch concentration of any grain in the world due to our damp climate; it has good storage qualities and can be used through the year, unlike sugar beet or potatoes, which can only be used for 4 months. Further, the Dorset\ Somerset border is an ideal location for the plant, with predominantly animal farmers to the north and east growing grain to be converted into cattle feed for dairy farmers who are more concentrated to the to west and south. It is anticipated that the maximum radius for utilised grain will be 40 miles and supplies will be delivered using transport powered by bioethanol. All very neat!
Unfortunately, this is a capital-intensive product with high production costs, and is produced on a different scale from fractional distillation, a continuous process, so the manufactures will be looking to Government for financial help. Although ethanol combustion produces less energy than the equivalent quantity of gasoline it also produces less pollution because it burns more efficiently. From April 2008 the Government will be looking for a 2.5% concentration of biofuels in petrol unless there is a by-out penalty, and by 2010 this will increase to 5%.
Green Spirit Fuels is expected to ferment 300,000 tonnes of grain each year to produce some 130 million litres of bioethanol , enough for one billion miles of motoring. The plant will also produce 120,000 tonnes of animal feed, and 97,000 tonnes of CO2 . It is exploiting a niche market and is a frontrunner in the UK in the race to produce sustainable energy. It has recently acquired a site Humberside and plans further expansion, so the next few years will be very exciting
This inspiring presentation was as ‘heart warming’ as any romantic meal and potentially will have a more lasting effect! John Waltham said that ‘there are more useful products in a grain of wheat than a drop of oil’ and it will be fascinating to see this all happening on our doorstep.
This was followed by a very concise talk by Michael Keating on the current state of the Sherborne Wind Energy Project.
When did you last see the Milky Way?
Europe from Space Poole Ferry Terminal
On Wednesday 10th January Sherborne Science Cafe heard a fascinating talk on Light Pollution presented by Bob Mizon, winner of the Galileo Award of The International Dark Skies Association.
Satellite photographs of Europe clearly pinpoint every large city as glowing masses of light. Nearer to home the lights of Poole and Bournemouth are so bright that medium sized newspaper print can be easily read 10 miles away.
This, Bob Mizon suggested, was due to overly bright lights in Poole ferry terminal, plus badly directed lighting aimed up towards the sky, rather than down towards the ground. Fortunately Dorset is soon to replace many of its road lamps with downward directed types which will benefit the night sky.
As a keen astronomer, Bob was very concerned that over 90 per cent of children today have never seen the Milky Way. Children are so unused to darkness, either inside or outside the home, that when he takes his travelling planetarium into schools, many are quite alarmed when the lights go out.
There is a national trend for brighter lighting, and it is often stated that bright lights deter criminals. Security cameras need high levels of illumination to produce clear images. However apparently there is no independent evidence to prove that bright lights do deter criminals, as can be seen from the high levels of crime in well illuminated city centres. Infrared cameras could be an alterative.
Photographs were shown of globe lighting, where dark areas were clearly seen under each lamp. Ideal spots for criminals to lurk, it was suggested. Whereas downward facing lamps give more even illumination, and are hence much safer.
The Campaign for Dark Skies is not against general lighting but is aiming for reduced wattage in better directed lamps. It has been calculated that if this were to be achieved nationally, then two power stations could be shut down! We would all also be able to see the Milky Way once again.